the factory has brutal production tolerances on all those parts just as the aftermarket does.
tuners have the 200% nozzle figured out, sure a live tuning session could make it better depending on the skill of the guy punching the keyboard, but it is not a requirement like a few are contending...
should allow you to put more fuel in the cylinder at the best timing point.
30 will take more time to get the same amount of fuel in. the discussion would be is the longer shot time better or worser
run what your tuner recommends and likes to tune
go to a different shop. no need to replace the motor or pull heads without proving there is an issue with the heads.
throw that coolant filter away, remove the oil bypass thing.
pressure test, find the coolant leak.